Studies of Nanoscale Nitride Thin Films

Recently scientific and technological interests in studying nitride semiconductor thin films has increased due to their wide-ranging structural, electronic, magnetic, and optical properties. At industrial level, this family of materials has been known for high corrosion resistance and hard coatings for harsh environments, but the recent knowledge about their structural, electrical, and magnetic properties increased interest in studying them. One such material is chromium nitride (CrN), which is from the transition metal nitride family. This material is a potential candidate for spintronic applications. PI is expert in growing chromium nitride thin films on different substrates by various state-of-the-art tools and characterizing their structural, electronic, and magnetic properties under different conditions. PI has studied magnetic properties of CrN in detail under a different project and have published related articles in several in peer-reviewed journals such as Physical Review B, Journal of Physics D: Applied Physics, etc. In this project, PI will investigate the structural and electronic properties of chromium nitride thin films. The main motivation is solving the long-standing controversy over the electronic properties of CrN thin films. Some researchers declare that the CrN is a good conductor at low temperatures whereas other report it as an insulator, and a group report observed semiconducting behavior at low temperature. In order to address this controversy, we will be growing a variety of high quality CrN thin films by RF/DC sputtering under different high purity nitrogen and argon ambient leading to different stoichiometric ratio of chromium and nitrogen in the samples. This will be an important step for understand the influence of nitrogen defects over the electronic properties. We will study structural and electronic properties of these samples at room temperature first and then will study their electrical transport properties in a range of temperature taking from room temperature to liquid helium temperature. This will be a comprehensive study for understanding the nature of conductivity of the samples at cryogenic temperatures. Given the currently high level of interest in the fundamental properties of chromium nitride, we expect that the results of these studies can have consequences for the characterizing the material for devices and thus for future nanoscale technologies. With a full understanding of the magnetic and electronic properties of CrN thin films, it may ultimately be possible to develop spintronic devices such as data storage, sensors for petrochemical industry, or other applications via exchange coupling, exchanging spring biasing suitable for operation in harsh environments.